1. Technical Field
The present invention relates to a liquid ejecting apparatus such as an ink jet type printer, and a controlling method thereof, particularly to a liquid ejecting apparatus which ejects liquid including a component, sedimentation of which sometimes occurs, and a controlling method thereof.
2. Related Art
For example, a liquid ejecting apparatus is an apparatus which includes a liquid ejecting head capable of ejecting liquid from nozzles and which ejects various types of liquid from this liquid ejecting head. As a representative apparatus of this liquid ejecting apparatus, there is provided an image recording apparatus such as an ink jet type printer (hereinafter, simply referred to as a printer) which includes an ink jet type recording head (hereinafter, simply referred to as a recording head) as the liquid ejecting head, and performs recording of an image or text by ejecting and landing liquid-type ink with respect to a recording medium (landing target) such as a recording sheet, from nozzles of the recording head.
In recent printers, there is an apparatus which is configured so as to correspond to various uses, using special ink other than general color ink including color materials of black (K), cyan (C), magenta (M), and yellow (Y) which are basic colors for forming text or an image. For example, a printer disclosed in JP-A-2002-351322 is configured to perform recording using white ink including a white pigment such as titanium oxide or silver ink including a metal pigment having gloss such as aluminum foil. The specific gravity of the color material of the white ink or the silver ink is greater than the specific gravity of the color material of the general color ink. Accordingly, in the white ink or the silver ink, the color material tends to be readily sedimented with a lapse of time. In addition, there are differences in degrees, but sedimentation of the pigments also occurs in general pigment ink. If the sedimentation of the color material (pigment) progresses, there is a concern that the ink will not be normally ejected due to clogging of nozzles. For suppressing such malfunction, in this type of printer, by applying a minute vibration pulse to a pressure generation unit (for example, a piezoelectric vibrator or a heater element) and driving the pressure generation unit in a period when the ink is not ejected, the ink in a pressure chamber and meniscus are minutely vibrated to a degree of not ejecting the ink from the nozzles. That is, the ink in the pressure chamber and the ink adjacent to the nozzles are agitated by this minute vibration.
As described above, in the printer employing the ink containing a component, sedimentation of which relatively readily occurs, it is desirable to suppress the sedimentation by executing the minute vibration operation as much as possible. However, if the minute vibration operation is continued, there is a problem that the ink is thickened. That is, since the meniscus of nozzles is exposed to the atmosphere, the ink adjacent to the nozzles is readily thickened. The entire ink in the pressure chamber is gradually thickened, by the diffusion of the thickened ink in the pressure chamber due to the minute vibration operation.
In addition, such a problem is not limited to the printer, and the same problem occurs in other liquid ejecting apparatuses having a configuration of ejecting liquid including a component, sedimentation of which sometimes occurs.
An advantage of some aspects of the invention is to provide a liquid ejecting apparatus which can suppress ejecting malfunction of liquid, by suppressing thickening of liquid and efficiently executing a minute vibration operation, in a configuration of ejecting liquid including a component, sedimentation of which may occur, and to provide a controlling method thereof.